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    <title>pol2des</title>
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    <center>Scilab Function</center>
    <div align="right">Last update : April 1993</div>
    <p>
      <b>pol2des</b> -  polynomial matrix to descriptor form</p>
    <h3>
      <font color="blue">Calling Sequence</font>
    </h3>
    <dl>
      <dd>
        <tt>[N,B,C]=pol2des(Ds)  </tt>
      </dd>
    </dl>
    <h3>
      <font color="blue">Parameters</font>
    </h3>
    <ul>
      <li>
        <tt>
          <b>Ds</b>
        </tt>: polynomial matrix</li>
      <li>
        <tt>
          <b>N, B, C</b>
        </tt>: three real matrices</li>
    </ul>
    <h3>
      <font color="blue">Description</font>
    </h3>
    <p>
    Given the polynomial matrix <tt>
        <b>Ds=D_0 +D_1 s +D_2 s^2 +... +D_k s^k</b>
      </tt>,
    <tt>
        <b>pol2des</b>
      </tt> returns three  matrices <tt>
        <b>N, B, C</b>
      </tt>, with <tt>
        <b>N</b>
      </tt> nilpotent 
    such that:</p>
    <p>
      <tt>
        <b>Ds = C (s*N-eye())^-1 B</b>
      </tt>
    </p>
    <h3>
      <font color="blue">Examples</font>
    </h3>
    <pre>

s=poly(0,'s');
G=[1,s;1+s^2,3*s^3];[N,B,C]=pol2des(G);
G1=clean(C*inv(s*N-eye())*B),G2=numer(G1)
 
  </pre>
    <h3>
      <font color="blue">See Also</font>
    </h3>
    <p>
      <a href="../control/ss2des.htm">
        <tt>
          <b>ss2des</b>
        </tt>
      </a>,&nbsp;&nbsp;<a href="../robust/tf2des.htm">
        <tt>
          <b>tf2des</b>
        </tt>
      </a>,&nbsp;&nbsp;</p>
    <h3>
      <font color="blue">Author</font>
    </h3>
    <p>F.D.;   </p>
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